Luckless Andrea Petkovic has been ruled out of the Australian Open after suffering a knee injury in the Hopman Cup - and created an unusual piece of tennis history.

With no German players available to take her place in the team, she is expected to be replaced by Donna Vekic of Croatia, the first time in the 25 years of Hopman Cup that a player has been asked to represent a nation other than their own.

The German had powered into the top 10 in the world last year when she suffered back and ankle injuries which forced her out of action for seven months, her ranking tumbling to 126 as a result.

She had to retire after winning the first set of her match in Perth against Australia's Ashleigh Barty, and scans have revealed she has ruptured her meniscus which means a month of recuperation and no trip to Melbourne.

"I had an MRI this morning and they found out it is a rupture of the medium meniscus," Petkovic said.

"They don't know yet if they have to trim it. If they do it will be fine and I will only be out for a month. I could probably be playing already after two weeks, hitting balls. That would be really great.

"If they have to sew it up again it will take two to three months, but nonetheless I'm quite relieved that it wasn't the anterior cruciate ligament as it was a very similar pain and symptoms to 2008 when I had my ACL torn in Australia.

"My team and I are able to take it as tragically funny. People are strange and actually get used to chaos in their life, and I got used to a lot of mess this year.

"Every bad thing that could happen has happened to me so there's nothing there to surprise me anymore. I'm just hoping I can have a quick recovery."